Electrode-Ceramic Interfacial Cracks in Piezoelectric Multilayer Materials

A thin electrode layer embedded at the interface of two piezoelectric materials represents a common feature of many electroceramic multilayer devices. The analysis of interface cracks between the embedded electrode layer and piezoelectric ceramic leads to a nonstandard mixed boundary value problem which likely prevents a general analytical solution. The present work shows that the associated mixed boundary value problem does indeed admit an exact elementary solution for a special case of major practical interest in which the two piezoelectric half-planes are poled in opposite directions perpendicular to the electrode layer. In this case, it is found that oscillatory singularity disappears, in spite of the unsymmetric characters of the problem, and electroelastic fields exhibit power singularities. Particular emphasis is placed on the near-tip singular stresses along the bonded interface. The results show that tensile stress exhibits the square root singularity along the interface whereas shear stress exhibits the dominant-order nonsquare root singularity. In addition, the present model indicates that a pure electric-field loading could induce the dominant-order singular shear stress directly ahead of the interface crack tip. [S0021-8936(00)00602-4]